Stacking mechanism



F. E. SIMPSON STACKING MECHANISM March 2 2, 1966 Filed May 8, 1963 5 Sheets-Sheet 1 wm mm mm Om mq 3w wN mmow mm @P Q. mm or 8 INVENTOR 4 FRANK asm sou BY Hw 1%. fi aZJ ATTORNEY March 22, 1966 F. E. SIMPSON 3,241,690

STAGKING MECHANISM Filed May 8, 1963 5 Sheets-Sheet 2 INVENTOR FRANK E. SIMPSON B M/W- ATTORNEY March 22, 1966 F. E. SIMPSON STACKING MECHANISM 5 Sheets-Sheet 3 Filed May 8, 1963 m un INVENTOR 4 FRANK E. SIMPSON BY 4 4 {,2 77-m/ ;& J

ATTORNEY United States Patent 3,241,690 STACKING MECHANISM Frank E. Simpson, Castro Valley, Calif., assignor to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed May 8, 1963, Ser. No. 278,873 12 Claims. (Cl. 214-6) The present invention relates to stacking mechanisms and more particularly to a mechanism adapted to continuously receive sheet material articles and place such articles into indexed stacks with each stack containing a predetermined number of articles.

Herefore, considerable difficulty has been experienced in the handling of sheet material articles such as cellophane or polyethylene bags which are extremely flimsy in nature and tend to resist the conventional stacking and transferring methods. The rapid forming and discharge of such sheet material articles by high speed commercial machines necessitates apparatus which is designed to continuously receive the articles, arrange them into manageable groups or stacks, and feed them forward for further use while maintaining them in an orderly fashion to facilitate subsequent handling. These functions must be accomplished at the high production speeds to which our modern machinery is geared.

It is, therefore, an object of the present invention to provide a mechanism for stacking and indexing flimsy, sheet material articles, such as cellophane or polyethylene bags, which are continuously fed into the mechanism at high rates of speed.

Another object of the present invention is to provide apparatus for arranging sheet material articles into separated or indexed stacks.

Another object is to provide apparatus for piling sheet material items in neatly arranged, uniform stacks, each containing a predetermined number of articles.

Another object is to provide a stacking mechanism particularly adapted to handle sheet material articles which are made of highly dielectric material and are consequently prone to accumulate a charge of static electricity.

Another object of the present invention is to provide a stacking mechanism which is adapted to receive articles continuously and at high rates of speed from machines of diverse types, which mechanism will pile such sheet material articles into stacks of predetermined number, and feed such stacks in indexed relationship to a proper position for their removal and storage.

Another object is to provide a stacking mechanism of the character indicated, which is readily adaptable to be operated in conjunction with diverse types of presently existing machinery.

These and other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, in which:

FIGURE 1 is a side elevation of the stacking mechanism of the present invention.

FIGURE 2 is a plan of the mechanism shown in FIG. 1.

FIGURE 3 is an enlarged section of a portion of the mechanism of FIG. 2 taken along lines 3-3 and showing the device in operative condition during the stacking and indexing of a plurality of uniform sheet-material articles.

FIGURE 4 is a diagrammatic showing of an article feed mechanism that may be used with the stacking mechanism of FIG. 1.

FIGURE 5 is an isometric of a portion of the mechanism of FIGURE 1.

FIGURE 6 is a fragmentary section taken along lines 6-6 of FIG. 1.

FIGURE 7 is a diagrammatic perspective of the counting or timing device for actuating the mechanism of FIGS. 1-5.

The stacking mechanism 10 of the present invention is designed to handle the output from a machine which continuously emits or feeds sheet material articles at high rates of speed. Such a machine, for example, may be one which forms bags, envelopes and like articles of thin material. While it is to be understood that the invention is not to be limited to apparatus for stacking any particular form of sheet material, it is particularly suited for use with sheet material articles of polyethylene or like substance which are flimsy or sleazy and, therefore, present special problems during the high-speed handling thereof. It should be noted that articles of such material are prone to acquire a charge of static electricity which interferes with their normal movement along conventional conveying and stacking apparatus.

The stacking mechanism 10 (FIG. 3) generally comprises a preliminary stacking and aligning station 11 at which the articles are received from an external feeding means and are operatively engaged by a compacting device 14 which cooperates with a fiat conveying belt 16 to transfer and remove the stacks after they are formed. During operation of the stacking machanism, sheet material articles are fed to the mechanism between the lower runs of a plurality of spaced endless ropes or belts 12 (FIGS. 3 and 4) and the upper runs of a plurality of spaced endless ropes or belts 13. This feeding unit is a conventional mechanism for advancing sheet material, the belts 12 and 13 being trained around pulleys 15, certain ones of which are driven by a vari-speed drive mechanism (not shown). As indicated in FIG. 4 one end of the upper belts 12 are arranged to be periodically raised through a cam actuated lever 17 to facilitate the gripping of an article which is delivered to the unit by the discharge mechanism of a polyethylene bag-producing machine or similar structure. The articles are fed to the stacking and aligning station 11 where they are guided and arranged in orderly fashion into a stack B. After a predetermined number of articles have been thus accumulated in the stack, the compacting device 14 is actuated to compress the stack and press it against the conveying belt 16. Consequently, once the stack is compressed to hold the individual articles together for conjoint movement, the conveying belt is actuated for a brief period of time to transfer the stack a short distance rearwardly to a position wherein its forward end underlies the stacking station so that a new stack of the sheet material articles may be allowed to accumulate upon and in offset relationship (FIG. 3) with the first stack. With this arrangement a plurality of overlapping, uniform stacks will be formed on the belt and may be conveniently removed at a location spaced rearwardly along the belt.

The supporting framework of the stacking mechanism is simple in nature comprising parallel fiat side plates 20, rear leg members 21, and forward supporting legs 22, all of which are rigidly joined together by means of transversely extending angle beams 24. Parallel support brackets 25 for supporting the compacting device 14 are mounted upon and extend upwardly from the side plates 20. The brackets 25 are adjustably mounted upon the side plates by bolts 26 (FIG. 1) which are adjustably positioned in slots 27 that are formed longitudinally in the side plates. The adjustability of the brackets permits the stacking mechanism to accommodate different lengths of sheet material articles as will presently be made clear.

The initial stacking and aligning station 11 includes a pair of guide members 28 (FIG. 2) mounted in parallel relation to the side plates 20 and directly adjacent to the conveying belt 16. The guide members are supported at their forward ends by an angular bracket 29 (FIG. 3) which extends between and is Welded to the side plates at the forward end of the stacker. Bags or other articles, which are fed from the belts 12 and 13, are guided between the plates 28 to a channel-shaped stop member 31 which is mounted on the brackets 25 by means of a support member 32 and bolts 34. As each article comes to rest in the stack B (FIG. 3) after being fed from the belts, it will be received with its leading edge abutting the stop member and its trailing edge supported by an inturned flange 35 of the angular bracket 29. By adjusting the position of the stop member 31 longitudinally of the machine through the adjustment of brackets 25 by sliding bolts 26 within slots 27, the mechanism will be able to accommodate articles of different lengths thereby enabling it to handle the output of feeding devices of various sizes and types.

The compacting device 14 which is carried by the adjustable supporting brackets 25 includes a pair of rotatable endless chains 37, each of which is mounted for rotation by an upper sprocket 39 and a lower sprocket 4t). Sprockets 39 and 40 are fixed to shafts 41 and 42, respectively, which extend through the support brackets 25 to locate the sprockets and their associated chains closely adjacent to the interior surfaces of the brackets. The shafts are mounted upon the brackets for rotation by means of conventional bearing members 44 aflixed to the brackets by bolts 45. It may be seen in FIGURE 3 that the lower shaft 42 is positioned so as to extend within and adjacent to the bottom of the channel-shaped stop member 31.

The compacting of a stack B, when a predetermined number of articles have been accumulated, is accomplished by rectangularly shaped bars 46 and 46a which are pivotally connected at their ends to certain of the links of chains 37. The bars are mounted at opposed positions upon the chains with one of the flat sides of each bar being maintained in a horizontal position parallel to the stack B when it is in the vertical runs of the chains. During the operation of the stacking mechanism, the chains are adapted to be intermittently driven through increments sufficient to move a bar at the position of bar 46 in FIG. 3 to the position of bar 46a. This permits one of the bars 46 or 46a to act upon and compress the leading edge of the preformed stack of articles B during each of the intermittent operations.

The stacks are fed rearwardly in the mechanism away from station 11 by the fiat conveyor belt 16 which is mounted upon the supporting framework by means of a roller 48 at the forward or receiving end of the mechanism and an adjustable roller 49 at the rearward or stackremoval end of the mechanism. The roller 48, which functions as the drive roller for the conveyor belt, is of conventional design and includes an axially extending shaft 51 which is keyed to the roller (FIG. for effecting its rotation. Shaft 51 is extended. through and is supported upon the forward end of the side plates 20 by conventional type bearings 53. The rearwardly positioned, adjustable roller 49, likewise, includes an axial shaft 55. This shaft is extended through longitudinal slots 56 in the side plates 20 and is mounted for movement within the slots by means of slidable bearing plates 58 (FIG. 1). The bearing plates 58 are adjustably mounted upon the side plates 20 by shouldered capscrews 60 which extend through four slots 59 in the corners of the bearing plates, each shouldered capscrew being threaded into the adjacent side plate. Each bearing plate 58 further contains an outwardly turned flange 62 for rigidly mounting a rod 63 that extends forwardly of the bearing plate parallel to the adjacent side plate 20. Each rod 63 is slidably received in a block 65 fixed to the side plate 20 at a position spaced forwardly from the adjacent flange 62. A compression spring 67 is disposed around each of the rods 63 between the block 65 and the flange 62 to bias the bearing plates 58, and hence the adjustable roller 49, in the rearward direction. When the conveyor belt 16 is depressed during the compaction of a stack of articles thereon, the roller will move forwardly against the urging of compression spring 67 to prevent overstretching of the belt.

The intermittent actuations of the compacting device 14 are accomplished by means of a continuously rotating drive chain 68 (FIG. 2) which is adapted to be operatively connected to a drive shaft 70 through an intermittently-energized one-revolution clutch 69 of conventional design. The clutch 69, when energized, will rotate the drive shaft 70 for one revolution to set into motion apparatus which will be described presently that controls the movements of the compacting device 14 and the conveyor 16. The drive chain 68 may be powered by any suitable source such as an electric motor, or it may be driven by a suitable power take-off shaft on the machine (not shown) which is feeding articles to the stacking mechanism.

FIGURE 7 depicts diagrammatically the timing or counting mechanism which energizes the one-revolution clutch 69. The shaft S is a shaft driven at a fixed speed which is directly related to the rate at which articles are fed to the stacking mechanism. For example, if a machine such as that shown in United States Patent No. 2,768,673 to Gaubert et a1. is used for feeding polyethylene bags to the stacking mechanism, the shaft S may be an extension of or driven from the shaft designated by the numeral 98 in the disclosure of that patent which shaft revolves one complete revolution for each bag produced. Reference may be had to said patent for disclosure of a bag making machine having a shaft driven in timed relation with bag-forming mechanism. The motion of shaft S is transferred through a worm 71 to a worm wheel 72 which is fixed to a shaft 73. The shaft 73 rorates a flat timing disc 74 which turns at a rate determined by the worm gear ratio. Disc 74 is provided with a plurality of depressions or notches 75 on its outer periphery which are covered by removable filler plates 76 screwed into the face of the disc. A normally open micro switch 77 is mounted at a point adjacent to the periphery of the disc, the switch including a movable roller 78 which rides along the edges of the disc and the filler plates 76. When a filler plate is moved so as to expose a notch at the periphery of the disc, the roller will enter the notch as the disc is rotated, thus closing a circuit through the micro switch and energizing a solenoid (not shown) controlling the one revolution clutch 69. The leads 79, 79a run to a power supply and to the energizing solenoid which is located in the one-revolution clutch mechanism. The notches on the timing disc are spaced so that the stacking mechanism may be actuated to obtain stacks of various different sizes. In FIG. 7, only one notch is exposed so that each stack will contain the maximum number of articles. As pluralities of notches are exposed in regular intervals about the periphery of the disc, the stacks that are formed in the stacking mechanism will contain a lesser number of articles per stack.

The solenoid-operated one-revolution clutch 69 which is actuated by a closed circuit through the micro switch 77 may be any of many types commonly available for the usage described including both magnetic clutches and those wholly mechanical in nature.

FIGURE 6 illustrates the connections from the drive shaft 70 to the operating portions of the stacking mechanism. The drive shaft is rotatably mounted within a bearing member 82 on the front supporting leg 22. The projecting distal end of the shaft has affixed thereto a spur gear 83 and a crank arm 84 (FIG. 1) which is rotatably pinned to the lowermost end of an upwardly extending rack 85. Fixed to the support leg 22 in parallel relationship to the drive shaft 70 is a stub shaft 86, and connected together for joint rotation upon the stub shaft are a sprocket 87 (FIG. 6) and a gear 88 that is adapted to mesh with the gear 83 on the drive shaft 70. Power during a single operating cycle, of the drive shaft 70 is transmitted through the gears 83 and 88 and the sprocket 87 to an endless chain 9% which is trained around the sprocketv The upper end of the chain is received around a second sprocket 92 which is fixed to the projecting end of the lower shaft 42 of the compacting device 14. The intermittent, one revolution actuations of the drive shaft 70, therefore, are transmitted to the drive chains 37 of the compacting device through the linkage described.

The conveyor belt 16 is positively driven during only the last half of the one revolution operation of the drive shaft 70. As viewed in FIGURE 5, the inner side of the upper portion of rack 35 is provided with teeth 9'5 for engagement with a pinion 96 that is rotatably mounted upon the projecting end of conveyor shaft 51. A U- shaped slide arm 98 is also journalled upon shaft 51 on each side of the pinion to receive the flat, outer side of the rack in sliding relationship. A conventional pawl and ratchet device is utilized to rotate conveyor shaft 51 only during the downward movement of the rack, said device including a pawl shaft 100 which carries a pawl 1M and is attached to the rotatable pinion 96. The leading edge of the pawl engages the teeth on a ratchet M33 rigidly attached to the shaft 51, while a torsion spring 104 maintains the pawl in engagement with the ratchet. The mechanism is initially positioned so that rotation of the drive shaft 70 will begin with the crank arm 84- and the rack 85 in the position shown in FIGURE 1, i.e., with the rack in its lowermost position. For the first half of the operating cycle the rack will move upwardly and rotate thepinion 96 in the clockwise direction, as viewed in FIG. 1, causing the pawl 101 to slide over the surface of the ratchet 193 without imparting rotational movement thereto. When the crank arm 84 reaches its highest point, the rack 85 will begin to descend and will rotate the pinion 96 in the opposite or counterclockwise direction and cause the pawl to engage the teeth in the ratchet for effecting its rotation. This, in turn, causes the shaft 51 andhence the drive roller 43 to be actuated to propel the conveyor belt 16 in the rearward direction over the last half of the operating cycle.

In operating the stacking mechanism of the present 1nvention, the device is placed adjacent the output end of a sheet material feeding mechanism such as a mechanism with feed belts 12 and 13 as viewed in FIGURES l and 3. The support brackets are then adjusted to accommodate the particular length of sheet material article being fed to the mechanism, the distance between stop member 31 and supporting flange 35 equaling or being slightly less than the desired length. After a predetermined number of articles have been fed from the belts l2 and 13 to the guide members 28 and are collected as a stack B, the timing mechanism (FIG. 7) is set to actuate the one-revolution clutch 69 causing the drive shaft 70 to be mechanically engaged with the continuously rotating drive chain 63 for one complete revolution. The first one half revolution of the drive shaft will drive the parallel chains 37 and their associated bars 46 and 46a, through the linkage described, while the conveyor belt remains stationary. This first half of the operating cycle brings the compressing bar 46 (as viewed in FIGURE 3) downwardly to a position approximately at the elevation of the lower shaft 42 to cause the leading edges of the articles in stack B to be tightly compressed together between the bar 46 and the stack or belt directly thereben'eath. During the second half of the operating cycle, the bar 46 will move in a semi-circular path to the position originally occupied by the bar 46a. Since, as previously pointed out, the conveyor belt 16 is also actuated during this period, both the bar 46 and the belt 16 will be moving rearwardly together along the stacking mechanism. It is particularly desirable that the bar 46 and the belt 16 move at the same rate of speed in the direction of the path of the stack B. That is to say, the linear speed of the conveyor belt should be equal to the speed of the bar in the horizontal direction Since the bar and the adjacent part of the belt move together through the last half of the operating cycle and follow approximately the same path, the actual speed of each at any given instant will be approximately the same in both magnitude and direction. When the relative speeds of both the belt and compressing bar are adjusted to accomplish the aforestated objective, the stack B will be transferred to its rearward position without disturbance to its original arrangement or shifting of the articles in the stack.

It is to be noted that the stack B is preferably transferred rearwardly only a limited distance and that it will maintain its overlapped relationship with the stack preceding it. Thus, as the operation continues, each stack will be placed in overlapped or indexed relationship with the stack ahead of it. As the stacks are moved rearwardly along the conveyor 16, their travel will be intermittent and greatly reduced in speed from the speed with which the individual articles are fed from the belts 12 and 13, and they may be conveniently removed by operators stationed at the far or rearward end of the mechanism.

During the one revolution operation of the drive shaft 70, the bar 46a will move to the position originally occupied by bar 46. Therefore, the bars 46 and 46a are alternately used to compress and move forward accumulate-d stacks of articles. The phantom line representations 16 and 46 of FIGURE 3 show the positions of the conveyor belt and compressing bar, respectively, at the point of greatest depression of the belt. At that time the adjustable roller 49 will be drawn to the position 49' (FiG. 3) to prevent overstretching of the belt.

It can be seen, therefore, that the stacking mechanism of the present invention provides a device which will separate and remove stacks of sheet material articles to indexed positions wherein they can be more conveniently handled. The device may be operated in conjunction with bag making machines or other mechanisms having feeding output lines adapted to feed sheet material articles at high rates of speed. Despite the rapid operation of the mechanism, the articles may be gathered and transferred in neatly arranged stacks for subsequent processing. Since the stacks are placed in overlapped relationship they will maintain their uniformity during travel on the conveyor belt and they may easily be removed by an operator working at the rearward end of the mechanism.

The invention having thus been described, what is believed to be new and desired to be protected by Letters Patent is:

1. A mechanism for the stacking and indexing of sheet material comprising conveyor means for continuously receiving sheet material articles from a feeding mechanism, means cooperating wtih said conveyor means to arrange said articles in a stack at a first position on said conveyor means relative to said feeding mechanism, means operable upon the accumulation of a predetermined number of articles in said stack for compacting said stack, and means arranged to operate in timed relation with said compacting means for advancing the conveyor means forward a predetermined distance while said stack remains in compacted condition to transfer said stack to a second advanced position relative to said feeding mechanism, said conveyor means and compacting means being arranged to move at the same speed in the direction of the path of the stack so that the stack may be moved without disturbance thereto.

2. A mechanism for the stacking and indexing of sheet material comprising conveyor means for continuously receiving sheet material articles from a feeding mechanism, means cooperating with said conveyor means to arrange said articles in a stack at a first position on said conveyor means relative to said feeding mechanism, compacting means positioned adjacent the leading edge of said stack at said first position, said compacting means including a pressure applying member for compacting said stack at its leading edge, and means arranged to operate in timed relation with said compacting means for advancing the conveyor means forward a predetermined distance after the compacting of said leading edge of the stack to transfer the stack to a second advanced position relative to said feeding mechanism, said pressure applying member and said conveyor means being arranged to move at the same speed in the direction of the path of the stack so that the stack may be moved without disturbance thereto, said compacting means travelling in a non-linear path during movement to said second advanced position.

3. A mechanism for the stacking and indexing of sheet material comprising conveyor means for continuously receiving sheet material articles from a feeding mechanism, means cooperating with said conveyor means to arrange said articles in a stack at a first position on said conveyor means relative to said feeding mechanism, a compacting means positioned adjacent to the leading edge of said stack and arranged to be actuated in response to the accumulation of a predetermined number of articles in said stack, said compacting means including a pressure applying member for compacting said stack at its leading edge, the actuation of said compacting means causing said pressure applying member to be driven through a first movement to com-pact said stack and a second movement to aid in transferring said stack to a second advanced position relative to said feeding mechanism, and means arranged to actuate said conveyor means during said second movement of the pressure applying member to cause said conveyor means to transfer said stack to said advanced position in cooperation with said pressure applying member so as not to disturb the articles within the stack.

4. A mechanism for the stacking and indexing of sheet material comprising conveyor means for continuously receiving uniform sheet material articles from a feeding mechanism, means cooperating with said conveyor means to arrange said articles in a stack at a first position on said conveyor means relative to said feeding mechanism, means operable upon the accumulation of a predetermined number of articles in said stack for compacting said stack, and means arranged to operate in timed relation with said compacting means for advancing the conveyor means forward a predetermined distance which distance is less than the length of the articles while said stack remains in compacted condition to transfer said stack to a second advanced position relative to said feeding mechanism, said conveyor means and compacting means being arranged to move at the same speed in the direction of the path of the stack so that the stack may be moved without disturbance thereto, said second advanced position of the stack partially overlapping said first position wherein stacks of uniform sheet material articles can be continuously accumulated in overlapping relationship.

5. A mechanism for the stacking and indexing of sheet material comprising means for continuously receiving a plurality of loose sheet material articles from a feeding mechanism and arranging the same in a stack at a first position spaced from said feeding mechanism, compacting means arranged adjacent said stack, said compacting means including a member mounted for engagement with said stack and adapted to be actuated in response to the accumulation of a predetermined number of articles in said stack for compacting said stack and for thereafter keeping said stack in compacted condition during the transference thereof to a second advanced position with respect to said feeding mechanism, and an endless belt conveyor arranged to move in response to said actuation of said member after the compaction of said stack for transferring the stack to said advanced position.

6. A mechanism for the stacking and indexing of sheet m t rial c mprising means for continuously receiving sheet material articles from a feeding mechanism and arranging the same in a stack at a first position spaced from said feeding mechanism, compacting means arranged adjacent to said stack, said compacting means including a member mounted for engagement with said stack and adapted to be actuated in response to the accumulation of a predetermined number of articles in said stack for movement in a first direction to compress said stack and for continued movement in a second direction for maintaining said stack in said compacted condition during the transference thereof to a second advanced position with respect to said feeding mechanism, and an endless belt conveyor for propelling said stack to said second advanced position, said conveyor including means operatively associated with said compacting means to cause said conveyor to be actuated conjointly with said movement in the second direction by said member.

7. A mechanism for the stacking and indexing of sheet material comprising means for continuously receiving uniform sheet material articles from a feeding mechanism and arranging the same in a stack at a first position spaced from said feeding mechanism, compacting means arranged adjacent to said stack, said compacting means including a member mounted for engagement with said stack adapted to be actuated in response to the accumulation of a predetermined number of articles in said stack for movement in a first direction to compress said stack and for continued movement in a second direction for maintaining said stack in said compacted condition during the transference thereof to a second advanced position with respect to said feeding mechanism, and an endless belt conveyor for propelling said stack to said second advanced position, said conveyor including means operatively associated with said compacting means to cause said conveyor to be actuated conjointly with said movement in the second direction by said member, said second position being advanced from said first position a distance less than the length of said uniform sheet material articles whereby stacks of sheet material articles may be continuously accumulated in overlapping relationship upon said conveyor.

8. A mechanism for handling stacks of sheet-like articles comprising an endless belt conveyor having a conveying surface adapted to receive a stack of articles, a compacting member mounted above said conveying surface and arranged for movement downwardly to press the stack against the conveyor and forwardly in the direction of advancement of said surface, means movably mounting one end of said conveying surface whereby said surface can yield downwardly as the stack is pressed thereagainst, and means for advancing said conveying surface forwardly the same distance longitudinally of said conveyor as said compacting member is moved longitudinally of said conveyor during the same interval of time.

9. A mechanism for handling stacks of sheet-like articles comprising an endless belt conveyor having a forwardly moving conveying surface, a compacting member mounted above said surface for movement in an orbital path having a first component of said movement directed downwardly to engage a stack of articles and press them against said conveying surface, a second non-linear component in the direction of forward movement of said conveying surface, and a third component directed upwardly away from said surface, and means for advancing said conveying surface and moving said compacting member through said orbital path.

10. A mechanism for handling stacks of sheet-like articles comprising an endless belt conveyor having a conveying surface movable in a predetermined direction and arranged to receive stacks of articles thereon at a receiving station, a first compacting member cooperating with said conveying surface for advancing a stack a distance such that the trailing end portion of the stack remains in said receiving station whereby the next stack of articles deposited on said conveying surface will partially overlie said first stack, and a second compacting member cooperating with said conveying surface for advancing both of said stacks simultaneously in said overlapped relation.

11. A mechanism for the stacking and indexing of sheet material comprising conveyor means for continuously receiving sheet material articles from a feeding mechanism, means cooperating with said conveyor means to arrange said articles in a stack at a first position on the conveyor means relative to said feeding mechanism, a compacting means positioned adjacent to the leading edge of said stack and arranged to be actuated in response to the accumulation of a predetermined number of articles in said stack, said compacting means including a pressure applying member for compacting said stack at its leading edge, the actuation of said compacting means causing said pressure applying member to be driven through a first movement to compact said stack and a second non-linear movement to aid in transferring said stack to a second advanced position relative to said feeding mechanism, and means arranged to actuate said conveyor means during said second movement of the pressure applying member to cause said conveyor means to transfer said stack to said advanced position in cooperation with said pressure applying member so as not to disturb the articles within the stack.

12. A mechanism for handling stacks of loose sheetlike articles comprising an endless belt conveyor having .a conveying surface movable in a predetermined direction and arranged to receive stacks of articles thereon at a receiving station, a first member movable vertically downward to compress said loose stack, said compacting member cooperating with said conveying surface for advancing a stack a distance such that the trailing end portion of the stack remains in said receiving station whereby the next stack of articles deposited on said conveying surface will partially overlie said first stack, and a second compacting member cooperating with said conveying surface for advancing both of said stacks simultaneously in said overlapped relation.

References Cited by the Examiner UNITED STATES PATENTS 1,076,726 10/1913 Welch 198162 X 2,672,079 3/1954 Chandler.

GERALD M. FORLENZA, Primary Examiner.

HUGO O. SCHULZ, Examiner. 

1. A MECHANISM FOR THE STACKING AND INDEXING OF SHEET MATERIAL COMPRISING CONVEYOR MEANS FOR CONTINUOUSLY RECEIVING SHEET MATERIAL ARTICLES FROM A FEEDING MECHANISM, MEANS COOPERATING WITH SAID CONVEYOR MEANS TO ARRANGE SAID ARTICLES IN A STACK AT A FIRST POSITION ON SAID CONVEYOR MEANS RELATIVE TO SAID FEEDING MECHANISM, MEANS OPERABLE UPON THE ACCUMULATION OF A PREDETERMINED NUMBER OF ARTICLES IN SAID STACK FOR COMPACTING SAID STACK, AND MEANS ARRANGED TO OPERATE IN TIMED RELATION WITH SAID COMPACTING MEANS FOR ADVANCING THE CONVEYOR MEANS FORWARD A PREDETERMINED DISTANCE WHILE SAID STACK REMAINS IN COMPACTED CONDITION TO TRANSFER SAID STACK TO A 